Observations and analyses on the thermal stability of (1-x)Pb(Zn1/3Nb2/3)O3-xPbTiO3 thin films

Relaxor ferroelectric (1 - x)Pb(Zn1/3Nb2/3)O-3-xPbTiO(3) ((1 - x)PZN-xPT) thin films with x = 0.1-0.6 were prepared on (001)-oriented single-crystal LaAlO3 (LAO) substrates using a poly(ethylene glycol) (PEG)-modified sol-gel method. The films of the different compositions were annealed at different temperatures with varied duration. The evolution of the crystalline structure of the films with different heating conditions was analyzed using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and micro-Raman spectra. Our experimental results showed that the thermal stability of the (1 - x)PZN-xPT perovskite phase degraded with reducing the PT amount and increasing annealing temperature and duration. A bond valence method for analyzing perovskite structural stability was developed with corrected bond lengths at the high annealing temperature. The observed thermal stability of the perovskite phase in the (1 - x)PZN-xPT system could be well explained accordingly.